17 Oct 2007

Malaria vaccine is safe, immunogenic and efficacious in young infants

Initial findings from studies to test a malaria vaccine in African infants are promising, conclude authors of an Article published early Online and in an upcoming edition of The Lancet.

Dr Pedro Alonso, Manhica Health Research Centre, Mozambique, amd Hospital Clinic of the Universitat de Barcelona, Spain, and colleagues, did a double-blind trial of 214 infants in Mozambique to test the safety, immunogenicity, and efficacy of the malaria vaccine RTS,S/ AS02D. Children were randomly assigned to received three doses of the vaccine or hepatitis B vaccine Energix-B (as a control) at ages 10 weeks, 14 weeks and 18 weeks, as well as routine immunisation vaccines given at eight, 12, and 16 weeks of age.

They found that the vaccine was safe (the primary purpose of the trial), since there were no vaccine-related serious adverse events in either the vaccine or control groups, nor an imbalance in unsolicited adverse events between the two groups. Further, they found that for children vaccinated the risk of contracting new malaria infections reduced by 65%—compared with a previous efficacy of 45% reported in a trial of children aged one to four years.

The authors point out that all study participants were provided with free-insecticidetreated bednets and their homes were sprayed with insecticide twice. They say: “The trial was undertaken in an area of high transmission, but in the context of renewed and intense malaria control activities...the future use and deployment of a malaria vaccine should be seen in the context of comprehensive malaria control programmes.”

They conclude that the study provides evidence of a strong association between vaccine induced antibodies and reduction of risk of malaria infection. They say: “This is of great significance because up until now, immunogenicity was a marker of response with no clearly pressoffice [at] lancet.com Please mention The Lancet as the source of this material Issued by Tony Kirby, Press Officer, The Lancet Press pressoffice [at] lancet.com Telephone: +44 (0)20 7424 4949/4249 proven relation to protection, which in turn could only be established with a clinical trial. This finding needs to be corroborated further in other trials, but this observation might be important in the clinical development plan of this vaccine.”

For Dr Pedro Alonso, Hospital Clinic of the Universitat de Barcelona, Spain, please contact Marc de Semir, Communication Office. T) +34 932275700 / +34 93627947528